I am interested in looking into the internals of Ipipe and RTnet but not
just yet. I will be switching to e1000 NICs fairly soon anyway so chances
are I'll be able to get a higher throughput then anyway. I will probably
revisit this later on and ask for your suggestions on tracing through RTnet
and Ipipe. Thanks!
-Rob
On 11/11/07, Jan Kiszka <[EMAIL PROTECTED]> wrote:
>
> Jan Kiszka wrote:
> > Robert Gubler wrote:
> >> Hello,
> >>
> >> I am calling send() at 500 usec intervals with 1514 byte packets (the
> MTU
> >> size). Occasionally send() will fail with errno set to: "No buffer
> space
> >> available."
> >>
> >> If I did my math right the theoretical maximum number of packets at 500
> usec
> >> intervals is approximately 4. So, at 1 packet every 500 usec I am
> sending
> >> at a rate approximately equal to 25 MBit/s.
> >
> > Hmm, maybe the NIC is a bit too slow with handing back the freed buffers
> > (unlikely, though). This problem would be a good candidate for runtime
> > analysis via LTTng - but the patches required for this are currently
> > still only suited for brave early adopters.
> >
> >> So I guess my first question is, can this buffer space, that the error
> >> refers to be increased? Have I really reached the maximum number of
> packets
> >> I can transmit?
> >
> > Please have a look at Documentation/README.pools.
> >
> > However, I would suggest trying to find out the reason for this buffer
> > shortage instead of only increasing the pools (not saying the latter is
> > wrong per se). An alternative approach might be the I-pipe kernel
> ^^^^^
> to LTTng
>
> > function tracer with a long backtrace range so that you can watch out
> > for packet submission vs. buffer releases before that error was
> > reported. This will also require to understand a bit of RTnet internals
> > and its data flow, let us know if you want to go this path and need more
> > help.
> >
> >> I am using a recently copy of RTnet (SVN revision 1139, I
> think). Also, I
> >> am using the rt_eepro100 module.
> >>
> >> -Rob
> >>
> >
> > Jan
> >
>
>
>
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